The present invention relates to an image formation system, more particularly to an image formation system which prepares an orthogonally projected image from a centrally projected image such as photographs, and prepares and amends an image map so as to be able to understand field conditions by dimensioning a map on the image and superposing images on the map. Note that in this specification of this application, “photograph” shall contain a wide concept such as “acquire digital image,” “detect digital image” and “take a picture.”
According to prior arts, drawings obtained by surveying in a field have been prepared by paper, a pencil and the like typified by a plane table survey. Moreover, in recent years, line drawings of the fields have been prepared by a combination of a survey instrument and a portable computer typified by a digital plane table. In such conventional digital plane table, in order to acquire an image necessary for performing an orthogonally projected image preparation and three-dimensional data such as a control point, a rough plan for surveying and photographing a pertinent region was made, or alternatively works such as the survey and the photographing were conducted in the field without making any plan.